Tubes omg tubes

curlyjoe2378 said:

What are suitable subs for tubes 20lf6 and 30kd6 oh and maybe 31js6c oh and could they be used together

Click to expand...

Sure, as long as the filaments connected in series total out to equal the approximate line voltage 112 or 220 VAC, there was a bifilar choke to keep the RF out of the house wiring and, the tubes are not "directly heated cathodes" you could do that; why hell, this is America you could do anything you want because you have 'freedom'....

Not much sure if "Freedom" equates to a "Good signal out".

BTW, I for got to ask exactly what kind of amp this was you are "working" on?
.

Why not give up on expensive hard to locate sweep tubes and convert to something not so hard to come by. I am thinking EL500,509,519 maybe????? Maybe switch over to a single modern tube like 3CX250, 4CX250 I forget which is which is which but you can easily pick up 4 or 5 of them fairly cheaply. This would allow you build a 1-2 tube amp and have plenty of spares to keep you happy for the rest of your life. Those little 250's will easily put out 410 watts and easily will do 205 watts all day long with decent cooling. SO 2 of them would easily exceed what most of the sweep tube amps could ever hope to put out baring 10-12 tube models.

You could easily convert to Russian Mil. Surplus tubes as well. A voltage doubler board and what ever filament voltage you need but do not have already could easily be dealt with!

I do not know about you but I am tired of doing the hunt for sweep tube alternatives. If you are lucky you can find 17 watt dissipation tubes to replace what was once 30-40 watts of dissipation tube tubes for half the output.....Oh my what a win.....Depending on the sweep tube you find you might still have to deal with socket mod's or fil voltage mod's.Plus a lot of these lower wattage tubes can not take the 700-990 volts to the plates most of them are 450V so you even have to mess with plate voltage....not to mention difference in bias voltage and even the tank circuit might need more or less capacitance added or removed.

Just saying the sweep tubes that are still in the $2-$11 range are usually either low power or take higher fil voltage then most other's in the same family.

from the tube numbers I d say it was a Varmit linear not sure which size though, maybe even a home brew